The present invention relates a stator structure of a reciprocating motor, and more particularly, to a stator structure a reciprocating motor in which an area of a magnetic path is enlarged by increasing an area of an inner core where flux flows.
A general reciprocating motor has a plane form of magnetic flux compared to a general motor which has a cubic structure of magnetic flux. A flat armature is linearly moved on a plane according to variation of the magnetic flux formed on a fixing part.
FIGS. 1A and 1B show an example of the reciprocating motor which includes a stator (S) having a hollow cylindrical outer core 10 and a hollow cylindrical inner core 20 inserted into the outer core 10, a winding coil 30 coupled inside the outer core 10, and an armature 40 having a permanent magnet 41 and movably inserted between the outer core 10 and the inner core 20.
In the conventional reciprocating motor constructed as described above, when a current flows to the winding coil 30, a flux is formed around the winding coil 30. The flux forms a closed loop along the outer core 10 and the inner core 20, and the permanent magnet 41 receives a force in the axial direction by a magnetic flux formed by the flux formed in the outer core 10 and the inner core 20 and the magnetic flux, that is, the interaction of the flux.
Then, as shown in FIG. 2, the armature 40 makes a linear movement in the axial direction between the outer core 10 and the inner core 20. As the direction of the current applied to the winding coil 30 is changed in turn, the armature 40 undergoes a linear reciprocating movement.
The outer core 10 forms a stacked body that a plurality of thin lamination sheets 11 with a predetermined shape make a hollow cylindrical form.
In order to couple the winding coil 30 to the outer core 10, a bobbin is used 50 in view of a simplicity of a production as well as for an electrical insulation.
The bobbin 50 is constructed that an annular groove at which a coil is wound is formed inside the coil winding part 51 formed in an annular shape to have a predetermined diameter and a terminal part 52 connected to an external power terminal part is formed at the side of the coil winding part 51.
The winding coil 30 is wound in the annular bobbin 50 in multi-layers, and the wound coil is connected to the terminal part 52.
The plurality of thin lamination sheets 11 constructing the outer core 10 are radially stacked to form a hollow cylindrical shape at the coil winding part 51 of the bobbin,
The inner core 20 forms a stacked body that a plurality of thin lamination sheets 21 having a predetermined form are radially stacked to form a hollow cylindrical shape. The inner core 20 formed as the stacked body is inserted inside the outer core 10 with a predetermined space therebetween.
The armature 40 includes a plurality of permanent magnets 41 coupled at equal intervals to the hollow cylindrical permanent magnet holder 42. The armature 40 is inserted to be linearly movable between the outer core 10 and the inner core 20.
When the reciprocating motor is driven, a flux flows to form a closed loop through the outer core 10 and the inner core, and at this time, if much load is taken to the motor, the amount of the flux is increased.
At this time, since the area of the magnetic path of the inner core 20 where the flux flows is smaller than that of the outer core 10, if the motor is overloaded, a core saturation occurs.
Thus, in order to prevent the core saturation, the magnetic path of the inner core 20, that is, the area where the flux flows, needs to be increased, for which the inner diameter of the inner core 20 may be reduced or the outer diameter of the inner core 20 may be increased.
As an example, as shown in FIG. 3, in case that the outer diameter of the inner core 20 is increased (from D1 to D2), the volume of the armature 40 including the permanent magnet 41 and the outer core 10 is increased, resulting in an increase in the amount of the permanent magnets which would inevitably cause an increase in the production cost.
As another example, as shown in FIG. 4, in case that the inner diameter of the inner core 20 (from D1 to Dxe2x80x22), there is a limitation to increase the area and the number of the thin lamination sheets 21 constructing the inner core 20 is reduced, resulting in that the area of the magnetic path is rather reduced.
Therefore, an object of the present invention is to provide a stator structure of a reciprocating motor in which the area of the magnetic path where a flux flows is maximized without increasing the overall volume of a reciprocating motor.
In order to achieve the above objects, there is provided a stator structure of a reciprocating motor including: a stator having a hollow cylindrical outer core and an inner core formed as a hollow cylindrical stacked body inserted inside the outer core; a winding coil coupled inside the outer core; and an armature with a permanent magnet attached to one side thereof movably inserted between the outer core and the inner core.
In order to achieve the above objects, there is further provided a stator structure of a reciprocating motor including: a stator having a hollow cylindrical outer core and an inner core inserted inside the outer core and having a plurality of overlap-type thin lamination sheets of which one side has a double faces and the other side has a single face are stacked in a hollow cylindrical form in a manner that the single face is positioned at the inner side and the double faces are positioned at the outer side; a winding coil coupled inside the outer core; and an armature with a permanent magnet attached at one side thereof, and movably inserted between the outer core and the inner core.
In order to achieve the above objects, there is further provided a stator structure of a reciprocating motor including: a stator having a hollow cylindrical outer core and an inner core inserted inside the outer core and consisting of a radially stacked part that a plurality of thin lamination sheets are radially stacked in a hollow cylindrical form and a plurality of annular lamination sheets with a predetermined width are stacked in a hollow and cylindrical form in the axial direction and combined in the inner circumferential face of the radially stacked part; a winding coil coupled inside the outer core; and an armature with a permanent magnet attached at one side thereof, and movably inserted between the outer core and the inner core.